<!DOCTYPE html>
<html lang="zh-CN">
	<head>
		<meta charset="UTF-8" />
		<meta name="author" content="wangbo" />
		<meta http-equiv="X-UA-Compatible" content="IE=edge" />
		<meta name="viewport" content="width=device-width, initial-scale=1.0" />
		<title>变量</title>
	</head>
	<body>
		<script>
			// js 脚本语言 -运行,没有变量类型的限制
			// java 编译.class -运行 静态语言(编译)
			let num = 10;
			console.log(typeof num);
			num = '张三';
			console.log(typeof num)
			num = true
			// 会返回变量类型字符串
			console.log(typeof num)
			// 利用typeof 判断变量的类型
			let wuxian = 10/3;
			let youxian = 10;
			// console.log(Number.isFinite(10/3))
			console.log(Number.isFinite(Infinity))
		</script>
	</body>
</html>
